CSC: COBE quadrilateralized Spherical Cube

This equal area projection shows an entire sphere with a minimum of
distortion by projecting it onto the six faces of a cube. The faces are
stored as the third dimension of the image and numbered, contrary to the
1-based FITS convention, 0-5 as shown in the diagram above. This projection
was developed to archive data from the COBE (COsmic Background Explorer)
satellite.